The present invention relates to an exposure apparatus used in a semiconductor manufacturing process for example, and to a substrate storage cassette positioning device for storing a substrate to be exposed with the exposure apparatus, and in particular relates to an exposure apparatus, a substrate storage cassette positioning device, and a method of transporting a substrate storage cassette, in which a substrate is transported in and out with a loader system relative to a substrate storage cassette positioned on an installation platform.
In exposure apparatus used in the photolithography process of the manufacture of a semiconductor device, in order to ensure efficient exposure of a photo mask or a reticle pattern on to a single lot wafer stored on a wafer cassette, a wafer loader system is generally provided for transporting the wafer in and out with respect to the wafer cassette.
Moreover, a reticle loader system for selecting a plurality of reticles and setting the reticle on the exposure apparatus is also provided with the exposure apparatus.
This type of loader system extracts a wafer with a robot arm or the like from a wafer cassette holding a plurality of wafers, and transports the wafer to a wafer stage, and also returns the wafer from the wafer stage back to the wafer cassette.
In order to ensure that the robot is able to accurately extract the wafer, the wafer cassette is positioned by installation at a predetermined location on an installation platform, which is aligned relative to the robot.
However in recent years, accompanying the development of large diameter wafers (of diameters of 300 mm, for example), a variety of wafer cassettes corresponding to these larger wafers have been developed and proposed.
One method of positioning this type of wafer cassette onto an installation platform comprises using kinematic coupling to ensure that the positioning on to the installation platform is carried out with a high level of precision, even if the transfer precision during installation on to the installation platform is rough, and this method is now employed as a standard practice amongst companies associated with semiconductor manufacture.
FIG. 10 shows an example of an installation platform and a wafer cassette positioned by kinematic coupling.
As is shown in the diagram, three slot members 2 each comprising a V shaped slot which widens out in a downward direction are provided at an interval of 120xc2x0 in a radial arrangement on the bottom surface of a wafer cassette 1.
Kinematic coupling pins 4 which engage with the V shaped slots of the slot members 2 are then provided on an installation platform 3, in positions corresponding to, and facing, the V shaped slots.
By installing the wafer cassette 1 down onto the installation platform 3, so that the V shaped slots and the kinematic coupling pins 4 engage, the wafer cassette 1 can be positioned at a predetermined location on the installation platform 3.
However, the following problems exist with the conventional type of exposure apparatus described above.
When an operator installs the wafer cassette 1 onto the installation platform 3, because the slot members 2 and the kinematic coupling pins 4 are obscured by the wafer cassette 1 when viewed from above, it has been necessary to confirm the positional relationship of the slot members 2 and the kinematic coupling pins 4 from side on, which takes considerable time.
Furthermore, although there is a limit on the positioning deviation permissible for positioning the V shaped slots onto the kinematic coupling pins 4, it is still possible to install the wafer cassette 1 onto the installation platform 3, even if this limit is exceeded.
In such a case, because the wafer cassette 1 ends up being positioned on the installation platform 3 in a location different from the predetermined location, the robot arm may interfere with the wafer when attempting to retrieve the wafer, resulting in damage to the arm and/or the wafer, or even to the body of the robot itself.
The present invention takes the above factors into consideration, with an object of providing an exposure apparatus, a substrate storage cassette positioning device, and a method of transporting a substrate storage cassette, which enable a reduction in the operational time associated with installing a wafer cassette, and wherein by ensuring the positioning of the wafer cassette in a predetermined location, damage to each of the sections can be avoided, and reliability can be improved.
In order to achieve the above object, the present invention employs a construction in accordance with the embodiments shown in FIG. 1 through FIG. 6.
A substrate storage cassette positioning device according to a first aspect of the present invention is a substrate storage cassette positioning device for positioning a substrate storage cassette (43) in a predetermined location on an installation platform (40, 41), comprising a guide section (59) for guiding the substrate storage cassette (43) into a predetermined location during the positioning of the substrate storage cassette (43).
Consequently, in a substrate storage cassette positioning device of the present invention, when the substrate storage cassette (43) is installed onto an installation platform (40, 41), the substrate storage cassette (43) is guided into a predetermined location by the guide section (59).
A substrate storage cassette positioning device according to a second aspect of the present invention is a substrate storage cassette positioning device according to the first aspect of the present invention, wherein positioning concave portions (52) are provided on the bottom surface (51) of the substrate storage cassette (43), and convex portions (57) which will freely engage with the concave portions (52) of the substrate storage cassette (43) are provided on the top of the installation platform (40, 41).
Consequently, in a substrate storage cassette positioning device of the present invention, the substrate storage cassette (43) is positioned in a predetermined location on an installation platform (40, 41) by engaging the concave portions (52) provided on the bottom surface (51) of the substrate storage cassette (43) with the convex portions (57) provided on the top of the installation platform (40, 41).
A substrate storage cassette positioning device according to a third aspect of the present invention is a substrate storage cassette positioning device according to either one of the first aspect and the second aspect of the present invention, wherein the substrate storage cassette (43) is positioned from above into a predetermined location on an installation platform (40, 41); the installation platform (40, 41) comprises a retaining member (55) for retaining the substrate storage cassette (43) in a predetermined location; the guide section (59) is made up of a sloped surface formed on the retaining member (55); and the substrate storage cassette (43) is guided into a predetermined location by the peripheral section of the bottom surface of the substrate storage cassette (43) contacting the sloped surface.
Consequently, in a substrate storage cassette positioning device of the present invention, when the substrate storage cassette (43) is installed from above onto an installation platform (40, 41), the peripheral section of the bottom surface of the substrate storage cassette (43) contacts the sloped surface of the guide section (59) of the retaining member (55) and is guided into a predetermined location, and is then retained in this predetermined location by the retaining member (55).
A substrate storage cassette positioning device according to a fourth aspect of the present invention is a substrate storage cassette positioning device according to either one of the first aspect and the second aspect of the present invention, wherein the substrate storage cassette (43) is positioned from above into a predetermined location on an installation platform (40, 41); the installation platform (40, 41) comprises a retaining member (55) for retaining the substrate storage cassette (43) in a predetermined location; the guide section (59) is made up of a sloped surface formed on the peripheral section of the bottom surface of the substrate storage cassette (43); and the substrate storage cassette (43) is guided into a predetermined location by the sloped surface formed on the substrate storage cassette (43) contacting the retaining member (55).
Consequently, in a substrate storage cassette positioning device of the present invention, when the substrate storage cassette (43) is installed from above onto an installation platform (40, 41), the sloped surface formed on the peripheral section of the bottom surface of the substrate storage cassette (43) contacts the retaining member (55) and is guided into a predetermined location, and is then retained in this predetermined location by the retaining member (55).
A substrate storage cassette positioning device according to a fifth aspect of the present invention is a substrate storage cassette positioning device according to either one of the third aspect and the fourth aspect of the present invention, wherein a suction mechanism (61) for suctioning dust from the top of the installation platform (40, 41) is provided near the retaining member (55).
Consequently, in a substrate storage cassette positioning device of the present invention, when the substrate storage cassette (43) is installed onto an installation platform (40, 41), then even if dust is generated when the substrate storage cassette (43) contacts the guide section (59), the dust can be suctioned off and expelled by the nearby suction mechanism (61).
A substrate storage cassette positioning device according to a sixth aspect of the present invention is a substrate storage cassette positioning device according to any one of the first aspect through the fifth aspect of the present invention, wherein an impact absorption material is provided on either the peripheral section of the bottom surface of the substrate storage cassette (43) or on the guide section (59), for softening the impact when the substrate storage cassette (43) contacts the guide section (59).
Consequently, in a substrate storage cassette positioning device of the present invention, when the substrate storage cassette (43) is installed onto an installation platform (40, 41), even if the substrate storage cassette (43) contacts the guide section (59), the impact on contact is softened by the impact absorption material, enabling a reduction in the dust generated at the time of contact.
A substrate storage cassette positioning device according to a seventh aspect of the present invention is a substrate storage cassette positioning device according to the first aspect of the present invention, wherein the guide section (59) is provided on at least one of the installation platform and the substrate storage cassette.
A substrate storage cassette positioning device according to an eighth aspect of the present invention is a substrate storage cassette positioning device according to the seventh aspect of the present invention, wherein the guide section (59) is a sloped surface of an attached member which is attached to the installation platform.
A substrate storage cassette positioning device according to a ninth aspect of the present invention is a substrate storage cassette positioning device according to the eighth aspect of the present invention, wherein the guide section (59) is a sloped surface formed on the substrate storage cassette.
A substrate storage cassette positioning device according to a tenth aspect of the present invention is a substrate storage cassette positioning device according to the first aspect of the present invention, wherein positioning at a predetermined location is carried out through the engagement of a first engagement member (53) which is provided on the substrate storage cassette, and a second engagement member (54) which is provided on an installation platform and which engages with the first engagement member (53).
An exposure apparatus according to an eleventh aspect of the present invention is an exposure apparatus which uses light from an illumination system for transferring an image of a pattern of a mask (25) through a projection optical system (24) and onto a substrate (22), wherein a positioning device (42) for a substrate storage cassette (43) according to any one of the first aspect through the tenth aspect of the present invention is provided for positioning the substrate storage cassette (43), with the substrate (22) stored therein, at a predetermined location on an installation platform (40, 41).
Consequently, in an exposure apparatus of the present invention, when the substrate storage cassette (43) is installed onto an installation platform (40, 41), the substrate storage cassette (43) is guided into a predetermined location on the installation platform (40, 41) by a positioning device (42) according to any one of the first aspect through the tenth aspect of the present invention.
A method of transporting a substrate storage cassette (43) to a predetermined location on an installation platform (40, 41) according to a twelfth aspect of the present invention, wherein the peripheral surface of the substrate storage cassette (43) and an attached member provided on the installation platform are brought in contact, and the substrate storage cassette (43) is then moved to the predetermined location.